Effects of tunable hydrophobicity on the collective hydrodynamics of Janus particles under flows
Effects of tunable hydrophobicity on the collective hydrodynamics of Janus particles under flows
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DOI：
10.1103/physrevfluids.8.050501
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发表时间：
2022-08
影响因子：
2.7
通讯作者：
Szu-Pei Fu;R. Ryham;B. Quaife;Y. Young
中科院分区：
文献类型：
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作者：
Szu-Pei Fu;R. Ryham;B. Quaife;Y. Young
具有非平衡自组织的活性胶体系统是生物学中一个长期存在的、具有挑战性的领域。为了理解流体动力学流动如何用于主动控制Janus粒子（JPs）的自组装，我们使用最近开发的用于悬浮在粘性背景流中的两亲JPs的多体流体动力学的模型（JFM，941，2022）。我们研究如何产生各种形态从调整JP-溶剂界面的疏水分布。我们发现JPs组装成单层、多层和条纹结构。为了介绍动力学，我们包括一个线性剪切流和一个稳定的泰勒-格林混合流，并测量集体动力学的JP颗粒在他们的（a）自由能从之间的疏水相互作用的JP，（B）订购的JP在其董事的排列方面的序参数，和（c）应变参数，捕获在组件中的变形。我们表征了JP结构的有效材料性质，发现单层结构在剪切流动下增加了取向顺序，多层结构表现为剪切变稀流体，条纹结构具有屈服应力。这些数值结果提供了见解的动态控制的非平衡活性生物系统具有类似的自组织。
Active colloidal systems with non-equilibrium self-organization is a long-standing, challenging area in biology. To understand how hydrodynamic flow may be used to actively control self-assembly of Janus particles (JPs), we use a model recently developed for the many-body hydrodynamics of amphiphilic JPs suspended in a viscous background flow (JFM, 941, 2022). We investigate how various morphologies arise from tuning the hydrophobic distribution of the JP-solvent interface. We find JPs assembled into uni-lamella, multi-lamella and striated structures. To introduce dynamics, we include a linear shear flow and a steady Taylor-Green mixing flow, and measure the collective dynamics of JP particles in terms of their (a) free energy from the hydrophobic interactions between the JPs, (b) order parameter for the ordering of JPs in terms of alignment of their directors, and (c) strain parameter that captures the deformation in the assembly. We characterize the effective material properties of the JP structures and find that the uni-lamellar structures increases orientation order under shear flow, the multilamellar structure behaves as a shear thinning fluid, and the striated structure possesses a yield stress. These numerical results provide insights into dynamic control of non-equilibrium active biological systems with similar self-organization.